Fasting and Health: Blood Pressure, Metabolism and More

Key points at a glance

• Buchinger therapeutic fasting is a treatment method, not a cure; whether it fits a given case is always clarified by the medical team at the Tannerhof.
• The fasting therapy guidelines (ÄGHE) list its use for, among other things, high blood pressure, metabolic syndrome, rheumatic disease, migraine and type 2 diabetes mellitus.
• In a large observational study of 1,422 fasting participants, mean blood pressure dropped noticeably and 84.4 percent of those with pre-existing complaints reported an improvement.
• In cancer, fasting comes into question only as an adjunct in certain stages, never as a stand-alone treatment.
• With ongoing medication and chronic conditions, medical supervision is not an add-on but a prerequisite — and that is exactly what the fasting week at the Tannerhof is built around.

What fasting and health is really about

Many people come to fasting not just to mark a break but with a specific health concern: blood pressure that has been too high for years, a metabolism out of rhythm, recurring migraine, a rheumatic condition. The question behind all of these is the same: can fasting actually move the needle here?

The honest, evidence-based answer is that for a range of chronic and metabolic conditions, Buchinger therapeutic fasting under medical supervision can have a positive effect. This is not a promise of a cure and no guarantee for the individual case, but a classification described in the fasting therapy guidelines. At Naturhotel Tannerhof, therapeutic fasting is offered in exactly this frame: medically supervised, always individual, embedded in the Body Detox programme. Anyone who wants to go deeper into the health background will find it in the Longevity at the Tannerhof programme and on the hub page Therapeutic Fasting and Schlanke Tanne.

The definition that holds it all together: Buchinger therapeutic fasting is the deliberate, time-limited abstention from solid food and stimulants. Instead of solid meals, herbal tea, mild vegetable broth, freshly pressed juices and plenty of fluids carry you through the day. It is not a zero-calorie diet and not primarily a weight-loss method but a treatment method, a cleansing on many levels and an encounter with yourself.

Why fasting touches the metabolism

To understand why metabolic concerns in particular are touched by fasting, it helps to look at what happens in the body. During fasting it works on two levels at the same time — levels that are often blurred together yet should be kept apart.

The first level is fat burning. When the readily available carbohydrate stores run down, within the first few days the metabolism switches from glucose to fatty acids and ketone bodies. The body increasingly draws its energy from its own reserves. The second level is autophagy — the body's own recycling and cleaning processes at the cellular level, in which cell components are broken down, reused and reorganised. Put more vividly: all the recycling processes are set in motion, cleaning happens everywhere — cellular, vascular, in connective tissue, gut, brain, liver and kidneys. Both processes occur together, yet describe different mechanisms.

This shift explains why values linked to metabolism move during fasting. In the large observational study by Wilhelmi de Toledo and colleagues, published in PLOS One in 2019 and carried out with 1,422 fasting participants over four to twenty-one days, fasting blood glucose fell significantly and settled at a mean of around 4.7 mmol/l, while ketone bodies as a marker of fat burning rose markedly. These kinds of shifts are why fasting is medically interesting for metabolic concerns — whether it fits the individual case, however, always belongs in the conversation with the medical team at the Tannerhof.

Possible indications under the fasting therapy guidelines

The fasting therapy guidelines were issued by the Ärztegesellschaft Heilfasten und Ernährung (ÄGHE), an association of physicians that gives therapeutic fasting its clinical foundation. First published in 2002 and updated in 2013, the guidelines describe methodology, patient selection, contraindications and medical supervision. On this basis — and supplemented by the experience of the Tannerhof medical team — the possible use of therapeutic fasting for the following conditions can be classified. Each of these statements is a clinical classification under medical supervision, not a promise of a cure:

• High blood pressure (hypertension). The guidelines describe a fasting-induced reduction in blood pressure in both overweight and non-overweight people with hypertension. In the PLOS One study, mean systolic blood pressure fell from 131.6 to 120.7 mmHg, and diastolic from 83.7 to 77.9 mmHg.
• Metabolic syndrome and metabolic disorders. Obesity, hypertension and disorders of fat and sugar metabolism are described as typical fields of application for fasting therapy.
• Type 2 diabetes mellitus. Fasting can favourably influence sugar metabolism; during fasting, according to the ÄGHE, those affected usually no longer require glucose-lowering medication — which makes the medical adjustment of medication all the more important.
• Rheumatic diseases. Several controlled studies have shown a pronounced improvement in symptoms and a reduction in inflammatory markers in rheumatoid arthritis.
• Migraine. The ÄGHE points to studies in which more than 90 percent of patients had significantly fewer or no migraine attacks for at least six months after a course of fasting therapy.
• Allergies, autoimmune diseases, asthma and food intolerances. Here too the fasting therapy literature available via the ÄGHE classifies a possible benefit.
• Depression and mood. An improvement in mood after fasting has been described and can be explained neurochemically via changes in serotonin metabolism.
• Cancer in certain stages. Here fasting comes into question only as an adjunct — never as a stand-alone or substitute treatment.

Weight loss does not appear on this list as a treatment goal in its own right: in therapeutic fasting it is a side effect that only lasts if combined with a follow-on strategy such as intermittent fasting or low carb.

What the evidence actually shows

A list of indications stays abstract as long as you don't know how robust it is. So it is worth taking a closer look at the observational study already mentioned, which has comprehensively documented the safety and efficacy profile of Buchinger fasting.

1,422 people were monitored over fasting periods of four to twenty-one days using the Buchinger method. Of the participants who returned a self-report, 404 named a pre-existing health complaint — and of these 404, 84.4 percent reported that their condition had improved noticeably. No severe or lasting adverse effects occurred; physical and emotional well-being rose significantly in all groups. A feeling of hunger was absent in 93.2 percent of participants.

The physical measurements can also be put into numbers. Weight fell by 3.2 kilograms (over five days) to 8.6 kilograms (over twenty days), waist circumference by 4.6 to 8.8 centimetres. The table below summarises the key mean values of the study:

The framing matters: this is an observational study under clinical supervision whose participants were screened in advance for contraindications. The figures describe what is possible under good conditions — they are not a promise for the individual person. Translating from the study to the individual case is precisely what the medical conversation is for.

Why medical supervision is the key here

Particularly with chronic and metabolic conditions, medical supervision is not an additional safety net but the core. During fasting the metabolism changes, and many medications — for example for blood pressure, blood sugar or anticoagulation — then need to be adjusted. Blood pressure that falls under fasting can mean a previously appropriate dose suddenly being too high. Anyone taking medication should therefore not fast without medical supervision. That is not an exclusion but the reason to put fasting in qualified hands.

At Naturhotel Tannerhof, therapeutic fasting is always medically supervised — an attitude grown across three generations of physicians. The doctors at the Tannerhof are experts in fasting; they monitor values and circulation as well as the individual course. It starts with the initial medical consultation on the first day of fasting, designed holistically: it covers the medical history, the physical examination including bioimpedance analysis to measure body composition and a review of medication, together with questions about why someone is fasting, what goals exist alongside the fast and what fasting experience there already is. Every person is different; the individual stands at the centre. If needed a follow-up consultation takes place, and at the end there is a closing consultation in which what has changed is evaluated and the transition into everyday life is discussed.

The length of stay is booked before arrival; the schedule within that frame can be coordinated together in the initial consultation and extended where there are health concerns. For such concerns more time is welcome — ideally ten days of pure fasting or more, with close medical supervision.

More than numbers: the accompanying programme

Fasting with a health concern is more than monitoring readings. The accompanying treatment programme at the Tannerhof is deliberately broad because a fasting week works on many levels. Medical applications include bioimpedance analysis, IHHT altitude training depending on the programme and, where medically appropriate, ozone autohaemotherapy. There are also compresses and wraps such as the liver-supporting hay flower wrap, aroma wraps, mud and warm packs, baths and pours such as the Kneipp alternating douche and magnesium-rich detox baths, plus massages such as the fasting massage, the detox massage with Königsöl or the acidosis massage, lymphatic drainage and reflexology, complemented by breathing therapy and sauna sessions. For the mental side, psychotherapeutic coaching, nature coaching, business and communication coaching and art therapy are on hand.

Movement remains part of fasting, in measured doses: moderate base endurance training and moderate strength training are available, as are yoga, Feldenkrais, tai chi and Theraband training. Summit hikes and running are possible, just at a pace that suits fasting — the body nourishes itself from within. The Tannerhof Spa with indoor pool, historic sauna house and the BadeHarpfe with its 25-metre outdoor natural pool — which opens the view between the Wendelstein and the Sonnwendjoch — stands for the quiet hours in between. Above all lies the place itself: Bayrischzell, the alpine meadow, the mountain stream, clean and pure mountain air. My hideaway in the mountains is the frame in which fasting and medical supervision amplify each other.

Carrying the effect into everyday life

A fasting week can set a lot in motion — but it only lasts if everyday life follows. That is especially true for metabolic concerns, where day-to-day nutrition is the biggest lever. Which follow-on nutrition fits is discussed in the closing consultation with the supervising doctors.

One path is Schlanke Tanne Low Carb, the Tannerhof's in-house low-carb cuisine. It is not a substitute for Buchinger fasting but a way to carry the fasting experience into everyday life — with protein, vegetables, good fats and the aim of eating differently again without diminishing the pleasure of eating. When, instead of going without, the focus is on gaining enjoyment and joie de vivre. Another path is intermittent fasting, for example in a 16/8 rhythm: again not a substitute for Buchinger but the recommended form for carrying the benefits of compact fasting into everyday life over the long term. Much of what the fasting week set in motion can be preserved well beyond the days at the Tannerhof. An overview is given on the hub page Therapeutic Fasting and Schlanke Tanne.